Validation of a code based data collection method in primary care for Influenza like illness surveillance in Belgium: Protocol, Nahimana, Mélanie, Bensemmane Sherihane, Rouvez Floriane, Debouverie Laura, Moreels S, De Schreye Robrecht, and Bossuyt Nathalie , Seminar on Infectious Disease , 2025, Issue Sciensano, Brussels, belgium, (2025)